Load push lift truck useable for depalletizing stacks of cartons of frozen animal products

ABSTRACT

A load push lift truck includes a push plate with sufficient clearance over its blades such that it can push a stack of cartons from a standard pallet when the blades of the lift truck are inserted in the four-way channels of the pallet. The clearance may be provided by a gate at the lower edge of the push plate that can be raised and lowered to increase or reduce the clearance of the push plate relative to the blades. A side shift mechanism may be provided to facilitate lateral positioning of cargo carried by the blades of the lift truck. A pallet retainer mounted on the lift truck to retain the pallet on the blades when the stacks of cartons are pushed from the pallet. A pallet stop mounted at the rear portions of the blades may be positioned to prevent a pallet from being pushed back on the blades beyond the face of the push plate.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation-in-part of thecopending application entitled “Method and Apparatus for Pallet Removal,Cargo Queuing and Stowage of Stacks of Cartons of Frozen AnimalProducts”, filed Apr. 23, 2003, Ser. No. 10/421,519, which is acontinuation-in-part of the copending application entitled “Method andApparatus for Loading Stacks of Cartons of Frozen Animal Products ontoVessels Using a Carrier”, filed Oct. 9, 2002, Ser. No. 10/268,182, whichis a continuation-in-part of the copending application entitled “Methodand Apparatus for Loading Stacks of Cartons of Frozen Animal Productsonto Vessels Using a Carrier”, filed Nov. 13, 2000, Ser. No. 09/712,741,which is a continuation-in-part of the copending application entitled“Method and Apparatus for Handling, Transporting, Pallet Removal, andLoading Cartons of Frozen Animal Products Onto Vessels”, filed Apr. 30,1999, Ser. No. 09/303,792, now abandoned, which is acontinuation-in-part of the issued patent entitled “Method and Apparatusfor Handling, Transporting and Loading Cartons of Frozen Animal ProductsOnto Vessels”, issued Nov. 9, 1999, U.S. Pat. No. 5,980,198.

BACKGROUND INFORMATION

[0002] 1. Field of the Invention

[0003] The present invention relates to the field of cargo handlingequipment, and in particular, to a load push lift truck that may be usedfor rapid depalletizing and loading of cartons of frozen animal productsonto a refrigerated vessel or into cargo containers.

[0004] 2. Background of the Invention

[0005] While there have been significant advances in the methodsemployed for the loading and unloading of vessels and cargo containers,the loading of refrigerated, cartonized cargo, and in particular, frozenanimal products has proved particularly difficult due to severalintractable problems. As a result, the transfer of the products from thepackers to their loading aboard a vessel or in a container is presentlycarried out by processes that involve high costs and significantexpenditure of manual labor, and which include bottlenecks that slow theprocess, that may result in product degradation or spoilage, and thatresult in long loading times for the product onto the vessel orcontainer. It is presently common for the handling of cartons of frozenanimal products to proceed as follows.

[0006] A large volume of animal products such as frozen chicken, turkey,beef, pork and seafood products (including livers, hearts, other parts,deboned meat and the like) are frozen and shipped within and exportedfrom the U.S. in relatively shallow, rectangular boxes. For example,chicken thighs, legs or quarters may be shipped in cartons of about 23.5inches in length by 16.5 inches in width by 4 to 6.25 inches in height(59.7 cm by 41.9 cm by 10.2 to 15.9 cm). A preferred standardized boxsize for use with the present invention would be 24 inches by 16 inches(61.0 cm by 40.6 cm) with the height of the box varied to hold theparticular products to be shipped. A box of such dimensions containingfrozen chicken parts may weigh on the order of 30 to 45 pounds (14 to 20kg).

[0007] As the cartons are generally filled fairly completely withunfrozen animal products, and the animal products are subsequentlyfrozen while in the carton, the cartons of frozen animal products tendto be comparatively resistant to compressive forces. The cartons mayalso be slightly distorted from their rectangular shape owing to volumechanges accompanying freezing and to their handling and stacking. Forsimplicity, reference will hereafter be made to cartons of frozenchicken, as other animal products may be handled in a similar manner.

[0008] Owing to the size restrictions imposed by standard trucks andtrailers, the cartons are normally stacked on 40×48 inch (102×122 cm)pallets in layers of five cartons arranged with two cartons placed onthe pallet in an end-to-end relationship beside three cartons placedside to side with their long axes perpendicular to those of the firsttwo cartons. While the exact size of the stack of cartons may varydepending on the exact dimensions of the cartons, stacks of cartons andlayers of such stacks will be referred to herein as having the foregoingdimensions or having a wider side of 48 inches (122 cm) and a narrowerside of 40 inches (102 cm). These dimensions are, however, approximate,and may vary not only depending on the box dimensions, but also fromsuch factors as bulging of the cartons of frozen chicken andirregularities in the stacking pattern. In general, however, the cartonshave a relatively low aspect ratio (length divided by height). Forexample, a 4″ tall by 16″ long carton would have an aspect ratio of0.25. This is significantly lower than, for example, the common appleboxes.

[0009] A palletload of cartons generally contains between about 10 to 12such layers of cartons. A palletload of cartons arranged in this mannerwould have five cartons per layer. A 12 layer stack of cartons weighing30 pounds (14 kg) would thus weigh about 1800 pounds (818 kg). Threesuch stacks of cartons would thus weigh about 5400 pounds (2454 kg,equal to 2.454 metric tons).

[0010] Although it is the general practice to use pallets havingdimensions of 40×48 inches (102×122 cm) in the frozen animal productsindustry, which facilitate loading thereof into enclosed vans ortrailers, 48×48 inch pallets (122×122 cm), which hold six rather thanfive cartons per layer, are sometimes used. In such case, the cartonsare generally arranged in layers, each such layer having two rows ofthree cartons with the three cartons of each row in side-to-sidearrangement.

[0011] The stacking pattern for either the 48×48 or 40×48 inch pallets(122×122 cm or 102×122 cm) may be varied, as by rotating it from layerto layer. For the 40×48 inches (102×122 cm) pallets, for example, thetwo end-to-end cartons may be arranged along one of the long edges ofthe pallet in one layer and along the other long edge in the next layer.

[0012] Presently, standard wooden pallets are typically made of threeparallel beams arranged with a center beam and two outer beams on eitherside thereof. Boards or other such support members are nailed, stapledor otherwise fastened to the upper and lower surfaces of the beamstransversely to the beams to form the upper and lower surfaces of thepallet. Lift channels extending parallel to the beams are thus formedbetween the upper and lower transversely-mounted boards. Apertures maybe provided in the beams along their lower edges and/or boards may beremoved from the lower pallet surface in the area of the apertures(“4-way apertures”) to permit insertion of lift truck blades into thepallet transversely to the beams and lift channels (these are oftencalled “4-way” pallets, as a lift truck can insert the lift blades intothe pallet from any of four directions).

[0013] The packer sends the fresh chicken parts in such palletloads to ablast freezer/cold storage warehouse. At the warehouse, the cartons arerestacked with spacers between the layers thereof. The spacers allow thecirculation of air between the layers of cartons. Once the cartons areso stacked, the palletload of cartons are transferred to a blastfreezer, which forces air chilled to about −40° F. (−40° C.) between andaround the cartons. The chicken parts should be cooled in the blastfreezer to 0° F. (−17.7° C.) and should be held at that temperature.When the freezing process is completed, the cartons are removed from theblast freezer and placed in a rotator. The load of cartons is thenrotated 90 degrees onto its side, the spacers are removed, and the loadof cartons is then rotated back to an upright position in which it restsonce more on the pallet. In order to facilitate transportation andstorage of the stacks of cartons, the stacks may be, and typically are,wrapped with a stretchable plastic film to help reduce sliding of thelayers of cartons relative to one another. Lift trucks are then used tomove the cartons of frozen chicken products and transport them into thecold storage warehouse.

[0014] When the time comes to load a ship, lift trucks are used toremove the palletloads of stacks of cartons of chicken parts from thewarehouse, and place them inside dry van trucks or truck trailers fortransportation to the dock or container-loading area. The trucks ortruck trailers are typically uninsulated and unrefrigerated, and thuscan provide a deleterious environment to the frozen product containedtherein if they are not soon loaded into a refrigerated ship. At thedock or loading area, the cartons are removed from the truck trailer bylift trucks. Alternatively, if the cold storage warehouse issufficiently near to the dock or loading area, the lift trucks maytransport the palletloads of stacks of cartons directly thereto.

[0015] In the hold, lift trucks engage the pallets and transport thepallets with their stacks of cartons to locations near where the cartonswill be stowed. Stevedores then manually remove the cartons from thepallets and stack the cartons without pallets for shipping. The palletsare then returned to the square of the hatch and are stacked to behoisted out of the hold and back onto the dock by the ship's gear. Thesquare of the hatch is the volume of space extending vertically downwardfrom the open hatch to the floor of the cargo hold.

[0016] This process is quite inefficient. Delays in bringing asufficient quantity of product to the dock and in unloading the cartonsfrom the truck can increase the time needed to load the vessel. Thespace constraints in the vessel limit the number of workers who can beengaged in stowing of the cartons, and thus may create a backup forproduct arriving at the dock. Excessive delays in loading which resultin the cartons being left on the dock or in the truck can allow theproduct to begin to thaw, which can result in spoilage or otherwiserender the product unmarketable. Delay in loading may also result inincreased condensation of moisture on the cartons which can complicatethe handling process. As the industry is seeking to use less wax on thecartons and to utilize paper-coated boxes, the damaging effect ofcondensation and internal thawing on the boxes is increased.

[0017] The breakage rate for pallets during this process is fairly high.As many as half of the pallets suffer some breakage, and this can resultin splintered wood, which may contain protruding nails, being left atthe warehouse, on the dock and in the cargo hold of the vessel.Additional work is thus required to collect the pallets and palletdebris, to extract it from the hold of the ship or remove it from thedock, and to repair or discard the broken pallets. Further, theexistence of pallet debris at the warehouse, on the dock, and inparticular in the hold of the vessel, presents a risk of injury toworkers.

[0018] Inefficient as this method of handling may be, there are a numberof constraints that have made it difficult to improve. The main problemencountered is that the holds of the ship are irregular both in theoverhead clearance and in the shape of the floor space. Not only doesthe overhead clearance of the cargo holds vary from ship to ship, andperhaps within a ship from hold to hold, the internal structure of thevessel and of the cooling system within it can result in overheadclearances that vary depending on the location within the hold.

[0019] Another difficulty in loading such cargoes is that the cartonsare typically stacked to a uniform height after blast freezing. This isnecessary for efficient use of the cold storage warehouse. This uniformheight is generally ten or twelve layers of boxes arranged on a lifttruck pallet, but it may vary somewhat from this number depending on thesize of the cartons. The cartons are unitized by wrapping them with astretchable plastic film that aids in transportation of the palletloadsby lift truck, etc. However, space on refrigerated vessels is at such apremium that the wasted space of such pallets is considered undesirable.Thus, it has been considered necessary to avoid stowing the cartons onthe pallets, and thus the practice of manually stowing the cartons inthe ship by restacking them without the pallets has persisted. Moreover,since the ceiling height of holds on ships varies, and is seldom equalto the height of the cartons when stacked for warehousing purposes, ithas heretofore been considered essential to manually stack the cartonsin order to obtain as complete a filling of the vessel as possible.

[0020] Cargo containers do not have the problem of irregular shape, buttheir packing by means of hand stacking in order to eliminate the use ofpallets has been an impediment to their efficient loading in terms ofspeed and workforce requirements.

[0021] Load push lift trucks have been used to push cargo off the lifttruck blades. A load push lift truck has at least two blades extendingfrom its lift mechanism. Load push, side shift lift trucks are known inthe art of specialty lift trucks. Such lift trucks are discussed, forexample, in U.S. Pat. No. 4,752,179 to Seaberg. Typically, the bladesare relatively broad, and may have relatively smooth or polished uppersurfaces to facilitate the sliding of the cartons thereon. A push plateassociated with the lift mechanism can be extended by means of hydrauliccylinders from a retracted position adjacent the lift mechanism to aposition adjacent the ends of the blades. If the stack of cartons isresting on the blades of the lift truck, the push mechanism may also beused to push the cartons off the blades and/or to extract the bladesfrom under cargo as the lift truck moves backward away from the desiredposition of the stack of cartons. Such a lift truck may include aside-shift mechanism which permits small lateral adjustments in theposition of the cargo to facilitate its precise placement. Suchload-push lift trucks are known in the art of specialized lift trucks.

[0022] Parent U.S. Pat. No. 5,980,198 of common ownership andinventorship, which is incorporated herein by this reference, describesthe lifting of palletless stacks of cartons into the hold of a shipusing cargo slings.

SUMMARY OF THE INVENTION

[0023] Lift trucks, and particularly load push or load push side shiftlift trucks may be used for handling of stacks of cartons on pallets andfor lifting palletless stacks of cartons.

[0024] One aspect of the invention provides a lift truck having a loadpush mechanism mounted thereon. The load push mechanism includes a pushplate for engaging the cartons in a palletized stack of cartons cargocarried by the blades. The lower edge of the push plate is mounted tothe push mechanism such that it has sufficient clearance above theblades to enable the push plate to engage cargo loaded on a pallet whenthe blades of the pallet are in the four-way channels of the pallet.

[0025] In another aspect, the clearance between the lower edge of thepush plate and the blades of the lift truck is such that the push plateengages the bottom layer of cartons in a palletized stack of cartonswhen the blades of the lift truck are in the four-way channels of thepallet.

[0026] According to other aspects of the invention, a pallet stop may beprovided on the lift truck to prevent the pallet from being moved to aposition in which it is partially beneath the retracted push plate of aload push lift truck. The pallet stop may comprise blocks of metalaffixed to the blades of the lift truck and having sufficient height toprevent the further entry of the blades into the four-way apertures of apallet. The load push lift truck may also include a side shift mechanismthat permits the lift truck operator to shift the blades of the lifttruck laterally with respect to the longitudinal axis of the lift truck.The lift truck may be equipped with pallet restraints for maintaining apallet on the blades of a lift truck while the push plate pushes a stackof cartons off the pallet. The push plate may also be vertically movableor equipped with a movable gate at the lower edge thereof that can beraised and lowered such that the clearance between the lower edge of thegate, and hence of the push plate, can be adjusted as desired.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a partial perspective view of a ship adapted to beloaded with stacks of cartons of frozen animal products.

[0028]FIG. 2 is a front elevation of a typical 4-way wooden pallet.

[0029]FIG. 3 is a side elevation of a typical 4-way wooden pallet.

[0030]FIG. 4 is a perspective view of a carrier according to oneembodiment of the invention.

[0031]FIG. 5 is a perspective view of the carrier of FIG. 4 being loadedwith stacks of cartons of frozen animal products by load push lifttrucks.

[0032]FIG. 6 is a perspective view of the carrier of FIG. 4 with a stackof cartons of frozen animal products being removed therefrom by a loadpush lift truck.

[0033]FIG. 7 is a perspective view of the carrier of FIG. 4 with cargoslings positioned in the fork channels thereof.

[0034]FIG. 8 is a perspective view of cartons being lifted from thecarrier of FIG. 4 using cargo slings.

[0035]FIG. 9 is a perspective view of cartons of frozen animal productsbeing landed in the square of the hatch of a ship.

[0036]FIG. 10 is a side elevation of an end portion of a cargo sling.

[0037]FIG. 11A is a front elevation of a light-weight carrier accordingto another embodiment of the invention bearing three stacks of cartons.

[0038]FIG. 11B is a top plan view of the carrier of FIG. 11A withoutstacks of cartons loaded thereon.

[0039]FIG. 12 is a side elevation of the carrier of FIG. 11.

[0040]FIG. 13 is a top plan view of a layer of cartons arranged in a 3-2pattern, with lifting zones shown in phantom.

[0041]FIG. 14 is a perspective view of a landing pad capable ofreceiving a single stack of cartons.

[0042]FIG. 15 is a perspective view of a landing pad capable ofreceiving three stacks of cartons.

[0043]FIG. 16 is a perspective view of a roller deck according to oneembodiment of the invention, showing three stacks of cartons beingremoved at the slinging end and two stacks of cartons being loaded fromthe side onto the roller deck at the loading end.

[0044]FIG. 17 is a perspective view of a pallet table positionedadjacent one side of a portion of a roller deck.

[0045]FIG. 18 is a perspective view of an end-loading roller deck beingloaded by a load push lift truck.

[0046]FIG. 19 is a perspective view of a double-wide, end-loading rollerdeck being loaded by a load push lift truck.

[0047]FIG. 20 is a perspective view of a depalletizer being loaded witha stack of cartons by a load push lift truck.

[0048]FIG. 20A is a perspective view of a roller depalletizer.

[0049]FIG. 21 is a perspective view of a stack of cargons being removedfrom the depalletizer of FIG. 20 by a lift truck.

[0050]FIG. 22 is a perspective view of a roller landing pad.

[0051]FIG. 23 is a perspective view of a landing pad with fork channelsfor lifting stacks of cartons from either the 40″ or 48″ side of stacksof cartons.

[0052]FIG. 24 is a sectional side view of a push plate for a load pushlift truck having a hinged lower gate.

[0053]FIG. 25 is a sectional side view of a push plate for a load pushlift truck having a telescoping lower gate.

[0054]FIG. 26 is a perspective view of a stack of cartons beingdeposited in a stowage location in the hold of a ship by a load pushlift truck.

[0055]FIG. 27 is a perspective view of a landing pad.

[0056]FIG. 28 is a perspective view of the lifting portion of load pushlift truck with a pallet restraint mounted to the blades.

[0057]FIG. 29 is a perspective view of a lift truck with a clamp-typepallet restraint.

[0058]FIG. 30 is a top plan view of the clamp-type pallet restraint ofFIG. 29 with parts broken away.

[0059]FIG. 31 is a side elevation of a load push, side shift mechanismfor a load truck with a gate at the lower edge of the push plate.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0060]FIG. 1 depicts a ship 10 tied up alongside a dock. The ship isprovided with ship's gear 12 for loading and unloading the ship 10. Theship's gear 12 is provided with a cable 14 that may be extended andretracted using a winch system (not shown). The deck 16 of the ship 10is provided with one or more hatches 18. The ship's gear 12 is used tolift cargo from alongside the ship 10 into the hold 20 of the ship 10.Typically, a ship 10 has a plurality of such holds 20, each of which isaccessible by means of a hatch 18. Ships used to transport frozenproducts are typically provided with refrigeration apparatus formaintaining the holds 20 at a low temperature.

[0061]FIGS. 2 and 3 are side elevation views of a standard 4-way pallet30, on which a variety of cargo may be stacked. Such pallets arecommonly used for holding and transporting stacks of cartons, includingstacks of cartons of frozen animal products, such as frozen chickenparts, frozen organ meat, such as liver and kidney, or other frozenanimal products. As is known in the art, the 4-way pallet 30 comprises acenter beam 32, which runs the length of the pallet 30, and two sidebeams 34 which likewise run the length of the pallet 30 and which aredisposed along opposite edges of the pallet 30.

[0062] The upper and lower surfaces 36, 38 of the pallet 30 are formedby a plurality of boards 40 which extend across the width of the palletand which are fastened to the beams 32, 34 by nails, screws or otherfasteners. Cutouts 42 are provided along of the lower edges of the beams32, 34. The boards 40 which make up the lower surface 38 of the pallet30 do not cover the area of the cutouts 42. As is well known in the artof cargo handling, a lift truck may lift the pallet 30 either byinserting its blades in the closed-top fork channels 44 (best shown inFIG. 2) and then using the lifting gear to raise the forks and thepallet 30. The pallet may also be lifted by inserting the blades (forksor platens) of a lift truck through the channels (“4-way channels”)formed by the cutouts 42 in the beams 32, 34 and then raising theblades.

[0063] A lift truck usable according to the present invention mayinclude two relatively flat blades which may conveniently have a widthof 4 to 8 inches (10.2 to 20.3 cm), and may include side shiftcapability. The blades may be smooth and polished, and may have roundedor tapered edges. The load push system should be sufficiently powerfulto push a full stack of cartons of frozen chicken parts or the like offof the blades and into a stowage location, such as a position atopanother stack of cartons.

[0064]FIG. 4 is a perspective view of a carrier 50 according to oneembodiment of the present invention. The carrier 50, which may be madeof rectangular steel tubing, steel I-beams and/or steel plate, ispreferably welded together, but may be made of other materials, such asaluminum, and may be assembled using bolts or other fasteners, or byother means known in the art. The carrier 50 is comprised of a base 52and an upright center stop 54. As shown in FIG. 4, the center stop 54 ofthe present embodiment includes a lower, generally rectangular section56 and a generally triangular lifting section 58. A clevis 62 it ismounted through an aperture in a plate 60 at the apex of the liftingsection 58. The clevis 62 is adapted to receive a hook 64 attached tothe free end of the cable 14 of a ship's gear 12 or other such liftingdevice.

[0065] The rectangular section 56 of the center stop 54 may be of anydesired dimensions, but in the present embodiment, is relatively thinand is approximately as tall and wide as a stack of cartons of frozenchicken parts or the like. The center stop 54 of the present embodimentmay have as great a height as may be conveniently use for the purposeshereof. As will be appreciated by those skilled in the art, an increasedheight of the center stop 54 will reduce the degree of tipping of thecarrier 30 under asymmetric loads, for example, when only a single stackof cartons mounted on one side only of the carrier is being lifted. Ofcourse, if the center stop 54 is too tall, such height may make thecarrier 50 difficult to transport and store, and may increase theoverall weight of the carrier 50.

[0066] The base 52 of the carrier 50 is generally planar in structure.The base 52 of the carrier 50 of the present embodiment may be made ofsteel plate, of steel plate welded to a frame made of rectangular steeltubing or I-beams, or the like, so long as it is sufficiently rigid tobear the weight of stacks of cartons of frozen chicken without undueflexure, and is sufficiently light that the combined weight of thecarrier and the cargo is within the load limits of the ship's gear 12.The center stop 54 is mounted transversely to the long axis of the base52 across the middle section thereof, and such mounting should besufficiently rigid to accommodate asymmetrical loads such as thosementioned above.

[0067] A plurality of fork channels 66 are formed in the surface of thebase 52 for receiving the blades of a lift truck. If lift trucks havingtwo forks are used, then the carrier 50 should be provided with two forkchannels 66 on each side of the center stop 54. If fork lifts with morethan two forks are used, then a corresponding number of fork channels 66should be provided on each side. It should be noted that a three-bladelift truck can lift a stack of cartons arranged in the 2-3 patterntypical for a standard pallet can have its blades spaced apart to liftthe stack of cartons from either the 48 inch side or the 40 inch side,although lifting the stack of cartons with two blades from eitherorientation is more problematic unless the blades are very broad and/orprecisely positioned under the load.

[0068] The depth of the channels 66 should be sufficient to allowinsertion of the lift truck blades therein beneath a stack of cartons offrozen chicken placed on top of the base 52 when the stack of cartons offrozen chicken are supported by the upper surface portions 68 of thebase 52.

[0069] The walls 70 of the sling channels 66 which face away from thebase 52 are angled upwardly and inwardly toward the center stop tofacilitate the sliding of stacks of cartons of frozen chicken onto thebase 52 of the carrier 50 and into contact with the center stop 54. Theouter edges of the base 52 function as pallet stops 72, as will beexplained in greater detail below.

[0070] While the carrier 50 is shown as having two areas for placementof stacks of cartons of frozen chicken, configurations having a greateror lesser number, such as one or three or four such areas, may bedesigned, as will be appreciated by those skilled in the art.

[0071] In one embodiment of a method according to the present invention,a carrier 50 is used to lift depalletized stacks of cartons of frozenanimal products. The embodiments of the invention will be described withreference to cartons of frozen chicken parts or frozen chicken forconvenience, even though they are applicable to other frozen animalproducts stored in similar cartons.

[0072] Referring next to FIG. 5, a load push lift truck 80 (or sideshift, load push lift truck) is used to lift a 4-way pallet 30 bearing astack of cartons of frozen chicken 82 by inserting the blades of thelift truck into the cutouts 42 of the 4-way pallet 30. The pallet 30 andstack of cartons 82 may then be lifted by raising the blades of the lifttruck. In the method of the present embodiment, the lift truck carriesthe pallet 30 to a position in which the side of the pallet 30 oppositethe lift truck 80 abuts or is in close proximity to the pallet stop 72of the base 52 of the carrier 50. The pallet 30 and stack 82 may then belowered to the ground and the stack of cartons of frozen chicken 82 maythen be pushed from the pallet 30 in a direction generally parallel tothe long axis of the boards 40 of the pallet 30.

[0073] The direction of sliding of the stack of cartons from such apallet 30 may be chosen to reduce abrasion of the lower surfaces of thecartons in the bottom layer of the stack of cartons to acceptable levelsconsistent with the maintenance of quality standards for the frozenproducts contained in the cartons. Tearing through of the cartons toexpose the frozen animal products is generally considered undesirable.Of course, if the upper surface of the pallet 30 is sufficiently smooth,or any edges are sufficiently beveled, the direction of sliding of thestack of cartons relative to the pallet 30 may not cause sufficientabrasion to the lower surfaces of the cartons to be of concern. Withstandard pallets 30, pushing the stack of cartons of frozen animalproducts 82 may be successfully accomplished without the use of slipsheets or the like.

[0074] Slip sheets present special challenges in the handling of cartonsof frozen animal products. First, the cost of the slip sheets is suchthat it is not generally economical to stow the stacks of cartons withthe slip sheets. Further, if the slip sheets are carried into the holdof a ship with the intent that they will not be stowed with the cartons,they must be collected and removed from the ship. Finally, if thecartons are carried into the ship with slip sheets on slings or bycarriers, and if they are thereafter lifted by lift trucks and stowedwith the cartons, they can block vertical airflow in the hold. As manyrefrigerated vessels depend on vertical airflow for cooling, this mayresult in improper cooling of the frozen animal products duringshipment, with attendant spoilage.

[0075] In one embodiment, the bottom of the push plate of the load pushlift truck 80 is provided with sufficient clearance over the blades ofthe lift truck that the push plate can engage the stack of cartons 82with the blades inserted into the four-way apertures in a standardpallet without engaging the pallet. Four inches (10 cm) of clearance ofthe push plate over the blades of the lift truck should be sufficientwith most standard pallets so that the push plate can pass over the topof the pallet without interference, but still engage the bottom layer inthe stack of cartons. Of course, if taller pallets are used, additionalclearance may be required.

[0076] According to the present embodiment, stacks of cartons 82 offrozen chicken 30 may be pushed off of pallets in this direction withoutundue damage to the lower surface of the boxes of the bottom layer ofthe stack of cartons 82. The inclined face of the walls 70 further aidin avoiding damage to the cartons. Should the leading edge of any of thecartons of the stack of cartons 82 droop in the fork channels 66 to alevel below the upper surface 68 of the base 52 of the carrier, theslope of the walls 70 of the fork channels 66 will urge the droopingcorners back upward to the level of the upper surface 68 of the base 52.The stack of cartons may be pushed into engagement or close proximity tothe center stop 54 of the carrier 50.

[0077] While the simultaneous loading of two stacks of cartons of frozenchicken 82 onto the carrier 50 by different lift trucks from oppositedirections will reduce the risk of the carrier 50 being pushed along thedock, it should generally be possible for one lift truck 80 to load thecarrier 50 without sliding it along the dock.

[0078] Of course, once the stack of cartons 82 is properly positionedrelative to the carrier, it could be caused to slide onto the carrier 50by a separate pushing or pulling mechanism that does not require thepresence of the lift truck. It should be noted that the pushingmechanism should be configured to push the cartons from the palletwithout pushing the pallet at the same time.

[0079] Still referring to the method of this embodiment, once thecarrier 50 is loaded, the ship's gear 12 can lift it into the hold ofthe ship 10. When the carrier 50 has been landed in the hold, as shownin FIG. 6, a load push lift truck 80 is then used to lift the stack ofcartons off the carrier 50 and to transport the cartons to the storagelocation. At this stage, either of two approaches may be taken. The loadpush lift truck 80 may initially deposit the stack of cartons 82 intheir final stowage location, with a view to stevedores subsequentlyfilling the remaining space atop the stack from a lift-truck-depositedstack of cartons 82 nearby, or the lift truck may deposit the stack in aconvenient location with a view to the stevedores breaking down thestack into two or more shorter stacks on top of which the load push lifttruck 80 may deposit a full stack of cartons 82, the combined height ofthe hand-stacked and lift-truck-deposited cartons filling the availablevertical space (see FIG. 26).

[0080] Of course, if the height of the hold space will accommodate twostacks of cartons 82, then the lift truck 80 may deposit both suchstacks of cartons 82 in their final stowage location. Providing the loadpush lift truck 80 with side shift capability allows for greaterprecision in the placement of the stacks of cartons 82. Such side shiftmechanisms shift the carrier and forks of a lift truck 80 laterally,usually by means of a hydraulic cylinder.

[0081] Two lift trucks 80 may be used to remove the stacks of cartons 82from the carrier 50, so that the carrier may be quickly returned to thedock for further loading. The cycle time of the ship's gear 12 or cranelifting the carrier can be significantly increased if the loading orunloading of the carrier 50 is delayed. If the carrier 50 is designed tocarry more than two stacks of cartons 82, of course, more lift trucksmay be used simultaneously to unload it, thereby minimizing the time thecarrier 50 remains in the hold. Similarly, the time the carrier remainson the dock can be reduced by using multiple lift trucks 80 in theloading of the carrier 50.

[0082] In order to deposit a stack of cartons 82 on the floor of thecargo hold, the lift truck operator moves the stack 82 into the desiredposition and lowers the blades of the lift truck to the floor. Ifnecessary, the side shift function can be used to position the stack inabutting relation with an adjacent stack or wall. The lift truckoperator then simultaneously actuates the load push mechanism and eitherbacks the lift truck away from the location or allows the load pushmechanism to push the lift truck back from the stack (assuming the frontof the stack is engaged with another stack or with a wall). The processfor depositing a stack of cartons 82 on top of another partial or fullstack is the same, except the lift truck positions the bladesimmediately above the full or partial stack on top of which the fullstack is to be deposited.

[0083] For stowage in irregular spaces, such as adjacent a sloping wall,in spaces too small for a full stack to be inserted or the like, thelift truck may deposit a full stack of cartons near such stowagelocation and the stevedores can stow the cartons in such areas by hand.

[0084] With reference to FIG. 9, when substantially all of the cargohold has been filled, apart from the square of the hatch, the lifttruck(s) and carrier 50 are removed from the hold, and the square of thehatch is filled by depositing stacks of cartons lifted by cargo slingsdirectly into the square of the hatch using the ship's gear 12. Somemanual stowage of cartons will likely be necessary, of course, as theceiling height under the closed hatch may not be fillable merely byloading full stacks of cartons one on top of another.

[0085] In another embodiment of the invention, the carrier 50 may beused on the dock to depalletize and provide slings about the stacks ofcartons 82 to be deposited directly into the square of the hatch withoutthe use of slip sheets. As shown in FIG. 7, slings 90 may beprepositioned in the fork channels 66 prior to pushing the stack ofcartons 82 onto the carrier 50, or may be drawn through the forkchannels 66 after loading of the carrier by means of a rod with a hookedend or the like. The fork channels 66 of the carrier 50 provide aconvenient means for positioning the slings and provide the ability toadd the slings either before or after loading of the carrier. Thecarrier 50 may also be used as a depalletizer in a refrigeratedwarehouse or in other locations, as a load push lift truck 80 may extendits forks through the fork channels 66 and lift the stack of cartons 82from the carrier 50.

[0086] As shown in FIG. 8, once the carrier 50 is loaded with stacks ofcartons 82, as previously described, and once the slings 90 arepositioned with respect to the stacks of cartons 82, a spreader bar 92mounted on the hook 64 at the end of the cable 14 of the ship's gear 12may be used to lift the stacks of cartons 82 into the ship's hold. Aplurality of hooks 94 are attached to the spreader bar 92 by lengths ofcable 96 for engaging the eyes of the cargo slings 90 for lifting of thestacks of cartons 82. If the slings 90 are properly positioned relativeto the stack of cartons 82, the stacks of cartons 82 will swing towardone another into abutting relation after they have been lifted free ofthe carrier 50 by the ship's gear 12. The stacks of cartons 82 may thenbe deposited in the square of the batch directly into their stowagelocation by the ship's gear, as shown in FIG. 9. While it may appearthat the cartons of the stack 82 would fall from the bottom of the stackwhen lifted by slings or the blades of a lift truck, it has been foundthat they do not tend to do so even when the stack of cartons 82 is notwrapped with the stretch wrap material.

[0087] Of course, the slings used to load the stacks of cartons into thesquare of the hatch may be left in the cargo hold, and this willfacilitate the offloading of the vessel. In such case, the cost of thecargo slings is offset by the lower labor and other costs achieved bythe practice of filling the square of the hatch in this manner.

[0088] In another embodiment of the invention, however, as shown in FIG.9, it has been found that the slings 90 may be recovered by lowering thespreader bar 92 sufficiently to remove tension from the slings 90,unhooking one end of the slings 90 from the hooks 94 and then drawingthe slings 90 from about the stacks of cartons 92 by lifting thespreader bar 92 using the ship's gear 12. In order to avoid urging thestacks of cartons 82 so deposited out of an abutting relationship withadjacent stacks, the ends 98 of the slings which are released may bethose which run between the deposited stacks of cartons and the adjacentstacks, as shown in FIG. 9.

[0089] As shown in FIG. 10, the eyes in cargo slings 90 are frequentlymade by folding the end portion 100 of the web material of which thesling is made back over a portion of the web material 102 in a loop andsewing or otherwise bonding the end portion 100 to the portion 102. Inone embodiment, cargo slings for use in loading the square of the hatchare made of a thinner material to avoid providing an excessively thickoverlapping portion, and the edge 104 of the end portion 104 is securelyfastened to the portion 102 of the sling 90 to reduce the tendency ofthe edge 104 to catch and peel away from the portion 102 when the sling90 is drawn between two abutting stacks of cartons. The end of the sling90 may also be cut at a diagonal before looping it back and affixing itto the portion 102.

[0090] Of course, the carrier 50 or a modification thereof (e.g., one inwhich the triangular top portion 58 of the center stop 54 was removed,or in which the entire center stop 54 itself was absent) could be usedto depalletize and provide slings around stacks of cartons 82. Theseslung stacks of cartons could then be lifted into a ship 10, landed on alanding pad, and stowed by a side shift load push lift truck in themanner described in U.S. Pat. No. 5,980,198 to Coblentz. That is, alanding pad such as that shown in FIGS. 14, 15, 27 (or multiples of sucha landing pad, as needed, in the event that multiple stacks of cartons82 are lifted at one time, e.g., as shown in FIG. 8) could be providedin the hold, the slung stacks of cartons could be deposited on thelanding pad, the slings could be removed from the stack of cartons bypulling them through the channels in the landing pad, and a load pushlift truck could remove the stacks of cartons from the landing pad byinserting its blades into the fork channels of the landing pad andraising the blades. The stack of cartons could then be stowed using thelift truck as hereinbefore described. As with the landing of stacks ofcartons in the square of the hatch, one end of each of the slings 90 maybe removed from the hooks 94, and the ship's gear 12 may then pull theslings through the channels formed in the landing pad and return them todockside for reuse.

[0091]FIG. 11 depicts a lightweight carrier 110 that may be connected toa ship's gear by the lift ring 112. The carrier 110 comprises a spreaderbar 114 connected to the lift ring 112 by two cables 116, 118. Aplurality of hooks 120 are mounted into the spreader bar 114.

[0092] Referring to FIGS. 11 and 12, the carrier 110 further comprises abase 122 on which are mounted a plurality of supports 124, which are ofsufficient height to form channels 126 extending across the base 122under the stacks of cartons 82. The supports 124 are of sufficient widthand depth to permit the blades of a lift truck to be inserted into thechannels 126 formed between them.

[0093] As can be seen from FIGS. 11 and 12, the stacks of cartons arearranged in a three-two carton stacking pattern commonly used forstacking cartons of frozen chicken on a standard 40 by 48 inch (102×122cm) pallet 30 with the 48 inch face of the stacks of cartons 82 beingshown in FIG. 11 and the 40 inch face being shown in FIG. 12.

[0094] As shown in FIG. 13, the three-two pattern comprises threecartons 128 arranged side-by-side with their long edges abutting oneanother. Two cartons 130 are arranged in end-to-end relation beside therow of the three cartons 128.

[0095] Cartons 128, 130 arranged in this manner (e.g., as the bottomlayer of a stack of cartons 82) may be lifted from the 40 inch (102 cm)sides of the pattern by inserting two slings or two lift truck bladesunder them, for example, in the two lifting zones 132 shown in phantomin FIG. 13. Three slings or three lift truck blades could be insertedunder the cartons of 128, 130 from the 48 inch (122 cm) side of thethree-two pattern of cartons 128, 130 by supporting them, for example,in the lifting zones 133 134, three of which extended transversely to belifting zones 132 and are likewise shown in phantom. When lifting astack of cartons with the bottom layer stacked in this manner usingslings or lift truck forks extending from one of the wider (48 inch-122cm) sides of the pattern, for security in lifting, three slings or forkplatens should be used so that each of the three side-to-side cartons128 is supported by one of the slings or platens.

[0096] Referring again to FIGS. 11 and 12, the base 122 is connected tothe spreader bar 114 by cables 132 which extend from connection pointsalong the spreader bar 114 to either side of the base 122 (best shown inFIG. 12). The carrier thus provides three load areas 134, 136, 138, eachof which is bounded on either side by two of the four pairs of cables132. The need for stiffness of the base 122 is thus reduced, as theweight of the three stacks of cartons 82 is supported at four locationsalong the length of each side of the base 122 rather than only in themiddle of or at the opposite ends of the base 122. This permits theweight of the base 134 to be sufficiently low to allow for the liftingof the three stacks of cartons 82 into the hold of a ship with athree-ton ship's gear 12 or crane. Of course, the inner two of the fourpair of cables 132 could be eliminated if a base of sufficient stiffnessis provided. Of course, depending on the capacity of the loading crane,a base 122 could be fashioned to allow for the loading of two, four orother numbers of stacks of cartons. Further, the depth of the base 122could be extended to allow loading of two stacks of cartons, one behindthe other, to provide for the lifting of four stacks of cartons in a 2×2pattern, or six stacks of cartons in a 3×2 pattern.

[0097] The carrier 110 may be loaded by a single load push lift truckmaking three trips to load the three stacks of cartons in each of thethree load. To do so, the lift truck would position each stack ofcartons 82 on its pallet 30 adjacent to one of the load areas 134, 136,138 of the carrier 110 and use the load push mechanism to push thecartons off the pallet 30 and onto the carrier 110 in like manner asdescribed above, and in a direction generally parallel to the boards 40comprising the upper surface of the pallet 30 so that the lower surfaceof the cartons is not abraded excessively.

[0098] Of course, if the sum of the thickness of the supports 124 andthe base 122 is less than the height of a pallet 30, the pallet 30 maybe rested on the surface of the dock proximate to or abutting thecarrier 110 while the stack of cartons 82 is pushed from the pallet 30onto the carrier 110. In such case, the stack of cartons 82 could bepushed onto the carrier 110 without having to rise over the edge of thesupports 124. This facilitates the process of pushing stacks of cartons82 onto the carrier 110.

[0099] If the combined height of the base 122 and supports 124 isgreater than the height of a pallet 30, the tops of the supports 124could be angled downward for a short distance at their ends to providean upwardly-inclined ramp extending from a height lower than or equal tothe height of a standard pallet. In such case, even if the upper surfaceof the pallet were lower than the height of the center portion of theupper surface of the supports 124, the edge of the stack of cartons 82would slide up the ramped surface of the supports 124 as the stack 82 ispushed onto the carrier by the load push mechanism or other mechanism.

[0100] After the stack of cartons has been pushed from the pallet 30onto the carrier, the blades of the lift truck are still extended underthe pallet 30. The lift truck may then retract the load push mechanism,raise the blades, carry the pallet to a holding location where itdeposits the pallet 30, and then retrieve another pallet 30 (or multiplepallets 30 in the case of a lift truck provided with multiple sets offorks) carrying a stack (or stacks) of cartons 82 for loading onto thecarrier.

[0101] To facilitate loading, the carrier may be positioned adjacent astop 140, such as the curb commonly found along the edge of a dock, or abackstop could be positioned adjacent the landing area for the carrier.The backstop may be of concrete, steel or other materials, so long as itis of sufficient mass and has sufficient traction on the dock to resistany tendency of the carrier 110 to slide backwards when being loaded.The backstop should be capable of engaging the base of the carrier toprevent its sliding and may have a planar vertical surface for resistingthe sliding of at least the first layer of cartons in the stack 82 offthe back of the carrier. This will make it easier for the operator ofthe lift truck to avoid pushing the cartons beyond the back edge of thecarrier and to prevent the carrier from sliding away from the lift truckas the stack of cartons are pushed onto it.

[0102] The speed of loading may be increased by use of a load push lifttruck having three pairs of forks and being capable of lifting threestacks of cartons 82 at a time. The stacks of cartons 82 may bepositioned with sufficient space between them that the lift truck canpick up three stacks of cartons 82 and push them onto the carrier 110 atthe same time with the load push mechanism. Alternatively, however, thelifting mechanism of the load push lift truck could be equipped with aside shift mechanism that moves the outer pairs of blades laterally inunison, and may also be provided with a shifter mechanism that permitsthe two outer pairs of forks to be moved respectively to the right andleft away from the center forks. In such case, the lift truck could pickup three stacks of cartons 82 that are positioned side to side, and, ifthe base has pairs of cables 132 extending between the load areas 134,136 and 136, 138, the shifter mechanism could be used to add the spacebetween the stacks 82 needed for the stacks of cartons 82 to clear themiddle two pairs of cables 132 that support the base 122 of the carrier.The side shift mechanism could be of assistance in positioning the threestacks 82 laterally with respect to the carrier 110 so that theclearance between the stacks 82 are centered on the middle two pairs ofcables 132.

[0103] The carrier 110 may then be lifted into the hold 20 of a ship 10using the ship's gear 12 or other crane. Once in the hold, three-bladelift trucks may be used to unload the carrier by inserting their bladesinto the channels 126 beneath the stacks of cartons and carrying them tostowage locations as described above. For greater efficiency, the lifttrucks may be load push lift trucks that can then deposit the stacks ofcartons 82 directly into desired stowage locations. Of course, whenpicking the stack of cartons 82 up from one of the the 48″ side, athree-blade lift truck can provide support to each of the threeside-by-side cartons the ends of which abut one another along the 48″side of the stack. The three-blade lift truck may also be used to liftstacks of cartons 82 from one of the 40″ sides of a stack, provided thecarrier or landing pad has fork channels that will accommodate the useof three blades (see, e.g., the landing pad of FIG. 27).

[0104] It has also been found that using three lift truck blades to lifta stack of cartons in the hold of a ship can be beneficial in thecarrying and maneuvering of the stack of cartons into a stowagelocation. In order to prevent thawing of frozen products during loading,the holds may be maintained at a sub-freezing temperature, and ice canform on the blades of a lift truck. During transportation of the stackof cartons 82 in the hold by a lift truck, the stack of cartons may thusslide laterally relative to the lift truck under such icing conditions.Such shifting has been found to be less likely and less serious when thecartons are supported during transportation by three blades rather thantwo. Modification of the blades to resist lateral sliding may alsopresent a solution to this problem. Flanges or channels runninglengthwise along the blade can provide additional resistance to lateralshifting of stacks of cartons on the blades.

[0105] When two such lift trucks are used in the hold of a ship,invariably one of them is working in greater proximity to the landingzone in which the cartons are deposited. Thus, one of the lift truckswill frequently return for another load before the other. Thus, it maybe desirable to carry three or more stacks of cartons into the hold at atime when using two lift trucks in the hold depending on how quickly thelift trucks can stow them. The addition of a third lift truck mayimprove the cycle time of the carrier 110 between the hold and dock,since the carrier may be unloaded more quickly.

[0106] The base 122 and spreader bar 114 may be shortened or lengthenedas desired to accommodate greater or lesser numbers of stacks of cartonsor to accommodate wider or narrower stacks of cartons in other stackpatterns. A base similar to the base 122 may also be used in anotherembodiment of the invention for palletless loading of other cargocarriers or for cargo storage facilities, as described in greater detailbelow.

[0107] As mentioned above, a carrier 110 may also be used to depalletizeand provide slings around stacks of cartons. The need for the crane orship's gear 12 to wait for the lift trucks in the hold of a ship tounload a carrier is not present if stacks of cartons 82 are lifted intothe hold using slings and landed on a landing pad as described above,since one end of each of the slings may be unhooked from the associatedhook and the slings may be drawn from around the stack of cartons 82even if the lift trucks have not returned to the landing area to carrythe stacks of cartons 82 away.

[0108]FIGS. 14 and 15 depict two such landing pads 140, 142 that areconfigured to receive up to one stack and three stacks of cartons 82,respectively, at a time. The landing pads 140, 142 of this embodimentcomprise a rectangular base 144 on which are mounted a plurality ofparallel supports 148 that can support stacks of cartons. The width andlocations of the spacers 148 on the base 144 are chosen such that astack or stacks of cartons 82 landed squarely on the landing pad 140,142 will be supported in a manner to permit lifting of the stack orstacks of cartons 82 by inserting the blades of a lift truck under thestack to be lifted and lifting it from the landing pad 140, 142. Thestack of cartons 82 may then be carried to a stowage location anddeposited as described above, and as shown in FIG. 26.

[0109] The channels 150 formed between the spacers 148 on the landingpads 140, 142 must be of sufficient depth that the forks of a lift truckcan be inserted under the stack of cartons, and must be of sufficientwidth to receive such blades. As the blades of a lift truck aregenerally thicker and wider than cargo slings, such dimensions allow theslings to be pulled through the channels without significant resistance.

[0110] As shown in FIGS. 14 and 15, the landing pads 140, 142 areconfigured for use by three-blade lift trucks for removal of stacks ofcartons stacked in a three-two pattern as discussed above. That is, theedges of the base 144 perpendicular to the long axis of the spacers 148are, respectively, about one and three times 48 inches (122 cm) inlength. Multiple units of the one-stack landing pad 140 could be boltedor otherwise fastened or positioned together to form a landing pad ofsufficient length to receive multiple stacks of cartons 82 if thedimensions of the base 144 and spacers 148 are appropriately chosen.

[0111] The landing pad 140, 142 could be provided with two or morechannels extending transversely to the supports 148 and channels 150, sothat two-blade lift trucks could be used to unload stacks of cartonsfrom the sides of the landing pads 140, 142 having only two channelstherein. However, the forks of a two blade lift truck would nottypically be of sufficient length to allow their insertion under thecenter stack of cartons on the three-stack landing pad 142 from eitherof the ends of the landing pad 142, as the forks would have to be 96inches (244 cm) in length to reach completely under the stack of cartons82 in the center position. A landing pad configured to receive three ormore stacks of cartons 82 and to have the stacks unloaded by two bladelift trucks from the long edge thereof could be made by adjusting thedimensions of the base 144 of the landing pad, the location of themounting of the supports and the width and thickness of the supports toprovide for landing and lifting of stacks of cartons 82 using two slingsand two blades, respectively.

[0112] While the carrier 50 or the base 122 of the carrier 110 or othersuch structure may be used to depalletize and provide slings aboutstacks of cartons 82 at dockside for lifting into the hold of a ship, itis also possible for the crane or ship's gear to be held up waiting fora full load of stacks of cartons to be readied for lifting into the holdof the ship. Multiple carriers 50 or bases 122 or the like could be usedto provide surge capacity for the crane or ship's gear. However, it ismore efficient for a crane or ship's gear to return to a single locationrather than having to return to multiple locations. In particular, gearused on many ships includes twin booms, one positioned over the hatchand one positioned over the loading area. Winches on each boom take inor let out their cable, as appropriate, to lift or land cargo atspecific, chosen locations, so that little effort is required to pick upand deposit cargo at the two chosen locations.

[0113] In another embodiment of the invention, and referring to FIGS.16-19, surge capacity for picking up one or more stacks of cartons at atime is provided by use of a roller deck that may also provide queuingcapacity. The roller decks of FIGS. 16-19 may be loaded either from theside or from the end, as discussed below. As shown in FIG. 16, a rollerdeck 160 according to this embodiment comprises a base 162 on which aplurality of rollers 164 are rotatably mounted. The rollers 164 aremounted with their rotational axes transverse to the long edge of thebase 162, and may be of a length sufficient to extend across the entirewidth of the roller deck 160, or may be segmented or may consist of aplurality of separate wheels rotatably mounted on the roller deck 160with parallel rotational axes. The rollers provide a low-frictiontransport surface so that stacks of cartons may be moved along thelength of the roller deck 160. This conveying of the stacks of cartonsmay be accomplished manually, with the assistance of gravity, or underpower. At the lifting (unloading) end 166 of the base, channels 168 areformed between sections of rollers 164 by spacing the rollers 164sufficiently that a cargo sling 170 or the blades of a lift truck can beinserted into the channels 168 under a stack of cartons 82. The upperportion of the long edge of the base 160 could be cut away at thelocation of such channels to provide additional depth for insertion ofthe blades of a lift truck.

[0114] If desired, channels could be formed by using segmented rollersspaced to form channels transverse to their rotational axes, alignedportions in which the diameter of the rollers is decreased sufficientlyto form useful channels, or, where wheels are used as rollers, thewheels could be omitted in certain areas to form such channels, suchthat lift truck blades or slings could be extended under the stack ofcartons.

[0115] The base 160 may be made in several sections, such as a liftingsection 172, a queuing section 174, and a loading section 176 forconvenient transportation and storage of the apparatus (the loadingsection 176 actually constitutes a queuing section in such case, inaddition to the queuing section 174, since a stack of cartons loadedthereon may be conveyed by the rollers to the queuing section 174 and onto the loading section 176). Of course, the queuing and loading sections174, 176 could be eliminated if queuing is not desired, and the liftingsection 172 could be loaded directly by the lift trucks However, thisembodiment of the invention will be described in connection with a base160 having lifting, queuing and loading sections 172, 174, 176 as it maybe advantageous in many circumstances to provide the queuing capacity toreduce the likelihood that either the crane or the loading lift truckwill be required to wait for action by the other.

[0116] These sections 172, 174, 176 could be aligned and fastenedtogether, as by using bolts or pins, when the roller deck 160 is to beused. Multiple loading and lifting sections 172, 176 could be providedwith different patterns of spacing of the channels 168 that could beselected according to the particular needs of the ship and cargo. Thesesections 172 could be attached to the other sections as desired, toprovide flexibility to the planners based on considerations relating tothe cargo, the ship, the available lift truck and other equipment andother factors. Different slinging or lift truck blade spacings couldthen be used to lift stacks of cartons 82 from the roller deck 160, asdesired. The width of the roller deck 160 should be chosen toaccommodate the width of the various stacks of cartons and otherarticles that may be deposited thereon.

[0117] An end stop 180 may be mounted to the base at the lifting end 166of the roller deck 160. The stop 180 limits the travel of stacks ofcartons 82 or the like along the bed of rollers 162 of the roller deck160, thus retaining the stack of cartons 82 on the roller deck 160, andallows the repeatable positioning of the stacks of cartons for liftingfrom the roller deck 160 for stowage. The stop 180 should be ofsufficient strength, width and height that it can stop the travel of astack of cartons 82 traveling along the roller deck 160 at a normalvelocity without causing damage, excessive distortion of the stack (asby one or more layers of cartons sliding relative to other layers) orloss of cartons from the upper layers. The stop may be of a singlepiece, or may be segmented to allow insertion of the blades of a lifttruck under a stack of cartons on the lifting section.

[0118] The upper surface 184 of the roller deck may be level orinclined. If the roller bed is sufficiently inclined, the stacks ofcartons can roll from the loading end 182 of the roller deck 160 to thelifting end 166 without the need for any mechanism to urge them towardthe stop 180. The roller deck 160 may be built with such an incline, maybe supported by a plurality of adjustable legs (not shown) along itslength, or may have spacers inserted beneath the base 162 at positionsalong its length to support the base 162 and upper surface Should any ofthe stacks of cartons 82 require assistance to reach the lifting end 166of the roller deck 160, the incline facilitates the manual pushing ofthe stack 82 to the lifting end 166 of the roller deck by a worker orworkers. A worker may also be tasked with pushing the stacks of cartonsalong the rollers 162 of a level roller bed 160 having a level uppersurface 182, or the rollers could be powered to transport stacks ofcartons along the roller deck 160.

[0119] Stacks of cartons 82 may be loaded onto the roller deck 160 fromthe side. As shown in FIGS. 16 and 17, a pallet table 190 may beprovided to facilitate the positioning of pallets 30 bearing stacks ofcartons 82 relative the roller deck 160 at the appropriate height and inthe appropriate plane. The pallet table 190 may be bolted or otherwiseaffixed to the roller deck 160, in which case, the vertical distancebetween the upper surface 192 of the pallet table and the adjacent uppersurface 184 of the roller deck 160 should be approximately equal to thethickness of a pallet so that the bottom of a stack of cartons beingpushed from the pallet 30 onto the roller deck 160 will not have to risein the process of the transfer from the pallet 30 to the roller deck160.

[0120] The pallet table 190 may be supported by adjustable legs 194which support it at the appropriate height and tilt relative to thesurface of the dock and the plane of the adjacent upper surface 182 ofthe roller deck 160. The legs 194 may include a screw portion 196 thatmay be rotated to adjust the length of the leg 194. A nut 198 may beaffixed to the screw portion 196 of the legs 194 to facilitateadjustment thereof. A plurality of such legs 194 may be used to supportthe base.

[0121] The plane of the upper surface 192 of the pallet table 190 mayeither be level with the surface on which it is placed, such as a dock,or leveled with the upper surface 184 of the roller deck 160 orotherwise. If the upper surface 184 of the roller deck 160 is tiltedwith respect to the surface on which it is placed, then the legs 194 maybe adjusted to tilt the upper surface 192 of the pallet table 190 suchthat it is in a plane parallel to that of the upper surface 184 of theroller deck 160. Depending on the width of the pallet table, one or morestacks of cartons 82 may be pushed onto the loading section 172 of theroller deck 160 at a time, as shown in FIG. 16.

[0122] A pallet stop 200 may be attached at the rear portion of thepallet table. A pallet 30 may be pushed into engagement with the palletstop 200 such that it is proximate to a roller 202 rotatably mountedeither to the roller deck 160 or to the pallet table 190. To facilitateloading, the upper surface of the roller 202 may be mounted such that itis equal to or higher than the plane of the upper surface 184 defined bythe rollers 164 of the loading end 182 of the roller deck 160.

[0123] A loading stop 206 may be mounted to the roller deck 160 alongthe edge opposite to the pallet table 190. The loading stop should be ofsufficient height and width to stop stacks of cartons from moving toofar across the roller deck 160 and to provide indexing for the stacks ofcartons 182 to align them with the long axis of the roller deck.

[0124] One or more stops 208, 210 may be provided to limit the travel ofstacks of cartons 82 along the roller deck 160. Many different types ofstops may be used. In the present embodiment, two flag stops 208, 210are provided. These stops comprise a square tubular receiver 212 mountedto the roller deck 160, and a flag stop portion 213 comprising a squaretube shaft 214 that can be inserted into the receiver 212, a flagportion 216 mounted on the shaft for engaging stacks of cartonstraveling along the roller deck 160 and a handle 218 for removing theflag stop portion 213 from engagement with the receiver 212. The shaft214 may be inserted into the receiver such that the flag portion 216extends transversely over the rollers 164 of the roller deck 160 forstopping movement of stacks of cartons 82 along the roller deck 160, andmay be removed from the receiver 212, rotated from such orientation andinserted such that the flag portion does not block the progress ofstacks of cartons 82 moving along the roller deck 160. Other types ofstops, such as stops insertable into, or raisable above the uppersurface of, the roller deck 160 through gaps between adjacent rollers,roller brakes that stop rotation of one or more rollers at desired stoplocations and the like may also be used. Alternatively, sections ofrollers 164 could be selectively powered to rotate and move the stacksof cartons 82 along the roller bed 160 to desired locations.

[0125] While the stop 200 may be used to restrain the pallet againstmovement toward the roller deck 160 during loading of the roller deck160, the lift truck may also carry restraints, as described below, toretain the pallet on the forks of the lift truck and restrain motion ofthe pallet toward the roller deck 160.

[0126] If the upper surface 192 of the pallet table is tilted relativeto the plane of the surface on which the pallet table 190 is positioned,a wheel ramp 218 may be positioned proximate to the higher side of thepallet table 190 such that a wheel of the lift truck 220 can be drivenonto it to tilt the lift truck by an angle to level the forks of thelift truck with the pallet table 190.

[0127] The roller deck 160 of the present embodiment may be used asfollows load push lift truck carrying one or more stacks of cartons 82on pallets 30 raises the pallets 30 above the level of the upper surface192 of the pallet table 190, positions the stacks of cartons above thepallet table 190 and lowers the pallets 30 onto the upper surface 192 ofthe table 190. The operator of the lift truck 220 then engages the loadpush mechanism 222 of the lift truck to push the push plate 224 forwardrelative to the pallet table and slide the stacks of cartons 82 over theroller 202 and onto the roller deck. The stacks of cartons 82 may bepushed into engagement with the load stop 206 to align them with thelong axis of the roller deck 160. The stacks of cartons then move or aremoved along the roller deck to a position intermediate the ends 166, 182of the roller deck 160 where they may be held by the flag stop 210 andqueued for moving to the lifting end 166 of the roller deck.

[0128] Cargo slings 170 may be placed in the channels 168 prior tomovement of stacks of cartons 82 into position above them, or may bepushed or pulled through the channels 168 between the rollers by ahooked rod or the like. Once the desired number of stacks of cartons 82are moved into position, with the endmost stack 82 abutting the end stop180, the ends of the cargo slings 170 may be attached to the cargo hooks230 of a spreader bar 232. The spreader bar 232 can then lift the stacksof cartons off the roller deck 160 and carry them into the hold of aship. Alternatively, the stacks of cartons could be removed from theroller deck by a lift truck, that would insert its blades into thechannels 168 and lift the stack or stacks of cartons 82 from the rollerdeck.

[0129] Further, the roller deck could be modified in the lifting zone bysegmenting the rollers such that a plurality of axially aligned rollersextend across the roller deck 160, and providing space between suchrollers to form channels therebetween for slings or lift truck bladesextending transversely of the rotational axes of the rollers 164.Rollers could also be formed with reduced diameters at selectedlocations to form such channels, or, if the rollers comprise a pluralityof wheels, such wheels could be spaced or omitted to form such channels.Such channels may be in addition to or in lieu of the channels 168 intowhich slings or lift truck blades may be extended. In order tofacilitate use of the channels extending transversely to the rotationalaxis of the rollers 164, the backstop 180 may be eliminated or modifiedso that it did not interfere with the inserting of the slings or lifttruck blades into the channels or the lifting of the stack of cartonsfrom the roller bed 160. Flag stops, or a series of upstanding stopscould be used for this purpose. Such a roller bed 160 could be used inthe hold of a ship or elsewhere to provide a landing pad with queuing.In such case, channels parallel and perpendicular to the rollers couldbe provided that would allow the landing of multiple stacks of cartons82 on the roller deck 160 at one end, and the lifting of such stacks ofcartons at that end or at the other end. In the latter case, the stacksof cartons could be rolled along the bed 160 to the other end to makeroom for the landing of more stacks of cartons 82 on the one end.

[0130] The roller deck 160 can be made in various lengths. Longer rollerdecks 160 can provide queuing of stacks of cartons to reduce delays ofthe ship's gear or other crane mechanism in waiting for a complete loadto be presented. In the present embodiment, moreover, the roller deck160 may be loaded with two stacks of cartons 82 at a time, while thespreader bar is adapted to carry three stacks of cartons 82 at a time.Thus, with its third load, the lift truck 220 would have deposited twoloads for the crane or ship's gear to carry into the hold of the ship.The roller deck 160 may also be used as a queuing landing pad for use inthe hold of a ship. In such case, channels could be provided in theloading area 176 in like manner to the channels 168 provided in thelifting section 172 It should be noted that the normal three-twostacking pattern of cartons on a 40″×48″ (102 cm×122 cm) and theorientation of the boards forming the top of the pallet may result inthe slings 90 passing under the stack of cartons in the 40″ (102 cm)direction. In such case, three slings 90 would be needed per stack 82,as the three side-by-side cartons of a layer should each be supported bya separate sling. When slinging under the 48″ (122 cm) width of thestack 82, only two slings are needed.

[0131] End loading of a roller deck 160 can be accomplished bypositioning the pallet table 190 adjacent the end of the roller deck160, as shown in FIGS. 18 and 19. Referring to FIG. 19, the pallet table190 may be made to accommodate two pallets at a time to be received froma double-wide load push lift truck 220. The double-wide roller deck 160can be made as a double-wide unit, or may comprise two single-wide unitsthat are positioned side by side. The slings 90 used to lift two stacksof cartons at a time, of course, would be longer than required forlifting a single stack of cartons at a time. The stretch-wrapping of thestacks of cartons 82 can facilitate the lifting of two stacks of cartons82 at a time by a single pair (or set of three) cargo slings 90.

[0132] As mentioned above, despite the weight of the stacks of cartons82, the base 52, 122 may be used to depalletize them without the needfor use of a slipsheet. Stacks of cartons 82 could be lifted into thehold of a ship from the base 50, 122 or from depalletizer platformshaving similar channels for slings and/or lift truck forks. Referring toFIGS. 20, 20A and 21, such depalletizer platforms 240 may include a base242 having a plurality of supports 244 similar in function to thesupports 124, 148 of the carrier 110 and landing pads 140, 142. Abackstop 246 may be provided to assist the operator of a lift truck 220to position stacks of cartons on the upper surfaces of the supports 244of the depalletizer platform 240. The platform 240 could also bepositioned adjacent a curb or free-standing backstop, as described inconnection with the carrier 110 of FIG. 11 to facilitate loading and toresist sliding of the depalletizer platform 240. The base 242 of thedepalletizer platform 240 may also include a pallet apron 248 ofsufficient size that the wheels of a lift truck carrying a loaded pallet30 would be driven onto a portion of the apron 248 when a pallet 30 ismoved into abutment with the outermost of the spacers 244. The weight ofthe lift truck 220 bearing on the apron 248 should control any tendencyof the depalletizer 240 to slide away from the lift truck 220 as thestack of cartons 82 is pushed from the pallet 30 onto the depalletizer240. The outward-facing edge (the edge remote from the backstop 246) ofthe supports 244 may be beveled to facilitate pushing of the stack ofcartons 82 onto the supports 244. The lift truck 220 may then retractthe load push mechanism, lift the empty pallet on the blades of the lifttruck 220 and take the empty pallet to a holding or stowage location.

[0133] While the stops 200, 206 provide an effective means forrestraining the pallet against motion when the stack of cartons 82 ispushed onto the roller deck 160, or otherwise off a pallet, other typesof restraints could be used. For example, as shown in FIGS. 28 and 29,restraints can be mounted on the lift truck. Referring to FIG. 28, therestraints 300 comprises metal bars of generally triangular crosssection mounted on the blades 302 of a lift truck. The rear surface ofthe restraint of this embodiment extends vertically upward from theblade. The forward surface of the restraint slopes upward and rearwardrelative to the blade to facilitate insertion of the blade 302 andrestraint into a 4-way channel of a standard pallet. The restraint ismounted on the blade 302 toward its rear, such that when the restraintis inserted into a 4-way channel of a pallet 38, and the blade 302 ofthe lift truck is raised, the back of the restraint 300 can engage theupper portion of the inner surface of the side beam 34 of the pallet 38to restrain the pallet against movement off of the blade 302. The palletcan be released by lowering the blade 302 and pallet 38 onto a surface.The blade can then be withdrawn from the 4-way channel 42 of the pallet38. The combined thickness of the restraint 300 and the blade 302 may bechosen to be such that the blade 302 and restraint may be inserted andwithdrawn from the four-way channel 42.

[0134] A pallet stop 304 may also be mounted on the blade 302. Thepallet stop 304 in the present embodiment is of rectangular crosssection and may have a length greater than the width of the 4-waychannel in the side beam 34 of the pallet and a height above the blade302 that is greater than the height of the 4-way channel so that thepallet stop 304 may engage the side beam 34 of the pallet 38 when theblade 302 of the lift truck is inserted into the 4-way channel of thepallet 38. The pallet stop 304 is positioned such that its forwardsurface is forward of the forward surface of the push plate 224 when thepush plate 224 is fully retracted, and prevents the blade 302 from beingpushed so far into the 4-way channel of the pallet 38 that the back edgeof the pallet 38 (the leftmost edge as shown in FIG. 28) is forward ofthe front surface of the push plate 224 when the push plate 224 is fullyretracted. The restraint 300 and pallet stop 304 may be mounted to theblades 302 of the lift truck and may be attached by a variety of meansincluding bolts or clamps, or by welding.

[0135] There must be sufficient clearance between the upper surface ofthe blades 302 of the lift truck and the lower edge of the push plate224 so that the push plate can be extended over the top of the pallet38. If the clearance is too great, however, the push plate may not beable to engage the first layer of cartons of frozen animal products, andmay instead engage the second and higher layers of cartons. This mayresult in the pushing of the second and higher layers of the stack ofcartons 82 off of the first layer, in whole or in part.

[0136] In another embodiment, and referring to FIGS. 29 and 30, arestraint 310 is mounted on a lift truck 220. This restraint 310comprises a housing 312 extending transversely relative to the blades302 of the lift truck 220. The forward surface of the housing 312 servesas a pallet stop in a manner similar to the pallet stop 304 shown inFIG. 28. Grippers 314 are slidably mounted in each end of the housing312 and are extendable and retractable relative to the housing 312 by ahydraulic cylinder. According to this embodiment, the pallet-engagingportion 316 of the grippers 314 is L-shaped, with the distal end portion318 of the gripper of the pallet-engaging portion 316 forming a rightangle with the lateral portion 320 of the pallet engaging portion 316.

[0137] The restraint 310 may be operated by the driver of the lift truckto extend and retract the grippers 314, as by a hydraulic cylinder 322mounted in the housing 312. The horizontal distance between the forwardsurface of the housing and the distal end 318 of the pallet-engagingportion 316 of the grippers 314 should be greater than the thickness ofthe side beams 34 of a pallet 38 when the grippers are in their extendedposition. The distance between the distal ends 318 of the grippers 314in the extend position should be greater than the length of the sidebeam 34 of a pallet 38 and less than the length of the side beam 34 whenthe grippers 314 are retracted. The distal ends 318 of thepallet-engaging portion 316 of the grippers 314 can thus be insertedinto the fork channels 44 of a pallet 38 to restrain the pallet 38 frommoving off the blades 302 of the lift truck when a stack of cartons 82is pushed from the pallet 38.

[0138] In the embodiment depicted in FIGS. 20 and 21, the depalletizeris configured to hold a stack of cartons 82 with a width of 48″ (122cm), the width extending parallel to the backstop 246, and a depth of40″ (102 cm). However, it could be configured to receive stacks of othersizes or orientations as desired.

[0139] In use, a load push lift truck positions a palletized stack ofcartons 82 with the far edge of the pallet 30 adjacent the outermost ofthe supports 244. The load push mechanism is then engaged, pushing thestack of cartons 82 from the pallet 30 onto the upper surfaces of thesupports 244. Slings can be positioned in the transverse channels 250 orlongitudinal channels 252 to lift the stack of cartons 82 from thedepalletizer. However, the stack 82 may also be removed from thedepalletizer by the blades of a lift truck inserted into the transverseor longitudinal channels 250, 252 formed between the spacers 244. Forlifting a 40″×48″ (102 cm×122 cm) stack of cartons 82 from the front ofthe depalletizer 240, with the 48 inch (122 cm) edge being the frontedge of the stack 82, a three-blade lift truck may be used with thetransverse spacing of its blades adjusted such that each one supports aseparate one of the three side-to-side cartons in the bottom layer ofthe stack of cartons 82. A two- or three-blade lift truck 220 may beused to lift the stack of cartons 82 from the depalletizer 240 byinserting its blades into the transverse channels 250.

[0140] The depalletizer platform 240 could be configured with a depth of48 inches (122 cm) and a width of 40 inches (102 cm) if desired, and ifthe pallet 30 is provided with a smooth upper surface, such as aplastic, plywood or metallic surface that permits pushing the stack ofcartons 82 off the pallet 30 in a direction parallel to the 48″ (102 cm)edge of the pallet 30. The depalletizer platform 240 could also besufficiently wide to accept multiple stacks of cartons 82 at a time. Asshown in FIG. 20A, rollers 245 (or a plurality of wheels) could be usedin a platform in place of the supports 244 to facilitate loading, withchannels 251 being formed between rollers by segmenting each of therollers into a plurality of segments and providing space betweensegments that can receive the blades 290 of a lift truck 220, by usingwheels as rollers, and omitting and/or spacing the wheels apart in theareas where channels are desired, and so forth. An upstanding plate orseries of plates 253 may be attached to the base 242 to provide a palletstop against which a pallet to be unloaded may be placed.

[0141] In one embodiment of the invention, a depalletizer platform 240is used for the loading of a shipping container or the like. Theinterior width of refrigerated shipping containers varies. Containerswith interior widths of from a little more than 88 inches (224 cm) tomore than 90 inches (229 cm) may be found. Such containers may be loadedby depositing pairs of stacks (or rows of stacks) of cartons 82 in theirinterior side by side with the 40 inch (102 cm) side of the stack 82being oriented perpendicular to the side wall of the container (“40+40loading”). The remainder of the width may be hand stacked in theremaining space between the stacks 82 or between a stack 82 and the wallof the container.

[0142] The stacks 82 could also be positioned with one stack (or row ofstacks) having its 48 inch (122 cm) side and one stack 82 (or row ofstacks) with its 40 inch (102 cm) side perpendicular to the side wallsof the container (“48+40 loading”).

[0143] As mentioned above, load push lift trucks that are used to pushstacks of cartons 82 from the pallets onto a carrier 110 or depalletizerplatform 240 (or even directly onto a deck, floor or other such supportsurface) must have push mechanisms with sufficient clearance over theblades so that the push mechanism does not engage both the stack ofcartons 82 and the upper portion of the pallet 30. The lift trucks thatlift the stacks of cartons 82 from a landing pad 140, 142, carrier 50,110 or depalletizer 240 have the bottom layer of the stack of cartons 82resting on the blades of the lift truck 220. As such, if the push plateof the lift truck has a clearance of, for example, 4 inches (10 cm) overthe blades, the push plate may not engage the bottom layer of the stackof cartons. This may be particularly important in the event that thestack of cartons are not wrapped with plastic wrap or the like. Thus,the lift trucks used in the hold of a ship may have load push mechanismswith lower edges having less clearance over the blades.

[0144] In another embodiment of the invention, the loading of acontainer can be accomplished using a depalletizer platform 240 and oneor more lift trucks 220. For 40+40 loading, a single, two blade loadpush lift truck could be used as follows. The lift truck 220 positions apalletload of cartons 82 on the depalletizer 240 and uses its load pushmechanism to push the stack of cartons 82 onto the supports 244 of thedepalletizer 240. The lift truck 220 may then retract the load pushmechanism and deposit the pallet 30 in a holding area. The blades 272 ofthe lift truck can then be inserted in the transverse channels 250 ofthe depalletizer platform 240, and the stack of cartons 82 may be liftedfrom the depalletizer and carried to a stowage location in a containeror the like. The stack of cartons 82 may then be deposited in thestowage location using the load push mechanism of the lift truck.

[0145] For 48+40 loading, a two-blade and a three-blade lift truck couldbe used. The lift truck with three blades would insert its blades intothe longitudinal channels 252 of the depalletizer 240, and lift andcarry the stack of cartons 82 to its stowage location. The two bladelift truck could then use the transverse channels 250 to insert itsblades under a stack of cartons 82 and to lift and carry it into acontainer or the like. The load push mechanism could then be used todeposit the stack of cartons 82 in the desired stowage location. Acontainer could thus have two parallel rows of 40 inch (102 cm) and 48inch (122 cm) width, respectively. If the stacks of cartons 82 are ofsuch height that they can be stacked on top of one another within thecontainer, then a second stack of cartons 82 may be brought into thecontainer by the lift truck 220 and deposited on top of a first suchstack by the load push lift truck. If the stacks of cartons 82 are ofsuch height that their combined height exceeds the interior height ofthe container, layers of cartons may be removed from stacks of cartons82 that have been deposited in their stowage location and may be handstowed to fill in other space in the container. After removal ofsufficient layers of cartons from the stack 82, a full stack can bedeposited on top of the remaining layers in order to take advantage ofthe headspace in the container.

[0146] According to another embodiment of the invention, the backstop ofthe depalletizer 240 may be taller than a stack of cartons to facilitateplacing of one stack on top of another. In such case, the lift truck mayposition the pallet carrying a second stack of cartons 82 atapproximately the level of the top layer of cartons in a first stackthat is resting on the depalletizer 240. The load push mechanism maythen be used to push the stack of cartons 82 off the pallet and onto thetop of the first stack of cartons 82. If desired, one or more layers ofcartons could be removed from the first stack of cartons 82 so that thecombined height of the first and second stacks of cartons 82 are of thedesired final height, such as the maximum height of a stack of cartonsthat can be loaded into a cargo container.

[0147] In accordance with another embodiment of the invention, and asshown in FIGS. 24, 25 and 31, a lift truck may be provided with a sideshift load push mechanism with a gate section 282 on the lower edge ofthe push plate 280. The side shift load push mechanism of thisembodiment incorporates a lift mechanism 350 capable of raising the sideshift and load push mechanisms 352, 354, as well as the blades 290. Thelift mechanism 350 is operated to raise and lower the side shiftmechanism 352 that, in turn, carries the load push mechanism 354 and thelift truck blades 290 by a hydraulic cylinder 356 (shown in phantom inFIG. 31). The side shift mechanism 352 includes a mount 358 attached tothe lift mechanism 350 and a slide 360 that is laterally slidable withrespect to the mount 358 and lift mechanism. A hydraulic cylinder orother motor (not shown) acts between the mount 358 and the slide 360 toallow the slide 360 to be moved laterally with respect to the mount 358.The blades 290 may be slidably mounted on the slide 360 so that thespacing between them can be adjusted as desired. The positioning of theblades 290 can be fixed relative to the slide 360 by bolts, clamps orother means.

[0148] The load push mechanism of the present embodiment comprises apush plate support 362 that supports a push plate 280 by means of ascissor mechanism 364. The scissor mechanism 364, in turn, may beextended or withdrawn to extend or withdraw the push plate. This isaccomplished by the hydraulic cylinder 366.

[0149] Greater or lesser clearance of the lower edge of the push plate280 over the blades 290 of the lift truck may be desired depending onthe task being performed by the lift truck. The gate section 282 of thepush plate 280 may be hydraulically activated, and may be of a type thatdoes not interfere with the operation of the load push mechanism. Forexample, as shown in FIGS. 24, 25 and 31, a hinged gate 284 or atelescoping gate 286 may be movable by one or more hydraulic cylinders288 between positions in which the lower edge 298 of the gate 284, 286is proximate to the blades 290 of the lift truck 220.

[0150] The gate 284, as shown in FIGS. 24 and 31, is pivotably mountedto the push plate 280 by a hinge 296. The hydraulic cylinder 288 ispivotably connected at its ends between the gate 284 and the push plate280 such that, in its fully extended position, the push plate is pivotedto a position in which it is parallel to the face of the push plate 280.When the hydraulic cylinder 288 is retracted, the gate 284 is raised toprovide maximum clearance between the upper surface of the blades 290 ofthe lift truck 220 and the push plate 280. Thus, the gate 260 can belowered to engage the bottom layer of a stack of cartons 82 beingcarried on the forks 290 of a lift truck 220, for example, fordepositing in a stowage location, or it can be raised to provideclearance so that the push plate may be extended to push a stack ofcartons 82 from a pallet, for example, onto a depalletizer such ascarrier 50, 110, roller deck 160 or depalletizer 260 with the forks 290in the 4-way fork channels.

[0151] The gate 286 operates in a similar manner, except that it isslidably mounted in and telescopes into the lower portion of the pushplate 280. The gate 286 is operated by one or more hydraulic cylinders,one end 288 of which is mounted to the push plate 280 and the other endof which is connected to the gate 286. The hydraulic cylinder 288 may beoperated to move the gate 286 vertically toward and away from the blades290 of the lift truck 220. Multiple gates 284, 286 may be used along thebottom edge of the push plate 280 if desired.

[0152] Where it is desired to use a load push lift truck 220 for pushingstacks of cartons 82 from pallets 30, the gate may be moved to itsretracted position. When a stack of cartons is carried directly on theblades 290 of the lift truck 220, the gate may be lowered to ensure thatthe push plate is able to engage the bottom layer of the stack ofcartons 82.

[0153] Of course, other methods may be used to provide variableclearance over the blades 290 of a load push lift truck. For example,the whole push plate 280 could be vertically movable with respect to theload push mechanism, or the load push mechanism itself could bevertically movable relative to the lift mechanism, or the blades of thelift truck could be lowerable (including by replacement of the blades)relative to the push plate 280. In any case, the variable clearance overthe blades of a lift truck may permit the lift truck to be used both fordepalletizing stacks of cartons 82 as well as for depositing the stacksof cartons in stowage locations. For lift trucks dedicated todepalletizing or stowage of stacks of cartons 82, an appropriate, fixedclearance of the push plate 280 over the blades 290 may be chosen.

[0154] The low profile of the cartons normally used for frozen animalproducts present challenges if sufficient clearance is not provided. Inthe case of pushing stacks of cartons from a pallet, too littleclearance may result in the push plate 280 engaging the pallet ratherthan the stack of cartons 82. Too great a clearance, of course, mayresult in engagement of the push plate with the second layer of cartonsin the stack 82, but not the first layer. This can result in sliding ofthe second and other layers of the stack of cartons 82 relative to thefirst layer.

[0155] While the present invention has been described with reference tovarious embodiments, it will be apparent to those skilled in the artthat modifications may be made within the scope of the invention.

What is claimed is:
 1. A load push mechanism for a lift truck havinglift truck blades mounted thereon and raisable and lowerable by a liftmechanism of the lift truck, the load push mechanism comprising: a pushmechanism raisable and lowerable by the lift mechanism; a push plate forengaging cargo carried by the lift truck blades, the push plate beingmounted on the push mechanism and being movable by the push mechanismbetween extended and retracted positions relative to the lift mechanism,the lower edge of the push plate having sufficient clearance over theblades when the push plate is in the retracted position that it can beextended over the upper surface of a standard pallet without engagingthe pallet when the blades are inserted in the four-way channels of thestandard pallet.
 2. The load push mechanism of claim 1 wherein theclearance between the blades of the lift truck is sufficiently smallthat the push plate can engage cargo resting directly on a standardpallet when the blades of the lift truck are extended into the four-waychannels of the standard pallet.
 3. The load push mechanism of claim 1wherein the distance between blades of a lift truck and the lower edgeof the push mechanism is changeable between first and secondconfigurations with at least one of such configurations providingsufficient clearance over the blades when the push plate is in theretracted position that it can be extended over the upper surface of astandard pallet without engaging the pallet when the blades are insertedin the four-way channels of the standard pallet.
 4. The load pushmechanism of claim 3 wherein the push plate includes a gate mechanismoperable between raised and lowered positions, the lower edge of thepush plate providing sufficient clearance over the blades when the pushplate is in the retracted position that it can be extended over theupper surface of a standard pallet without engaging the pallet when theblades are inserted in the four-way channels of the standard pallet whenthe gate is in its raised position.
 5. A load push lift truckcomprising: a truck; a lift mechanism mounted on the truck; at least twolift truck blades raisable and lowerable by the lift mechanism; a loadpush mechanism raisable and lowerable by the lift mechanism andextendable over the blades, the load push mechanism comprising a pushmechanism and a push plate for engaging cargo carried by the lift truckblades, the push plate being mounted on the push mechanism and beingmovable by the push mechanism between extended and retracted positionsrelative to the lift mechanism, the push plate having a lower edge andforward surface, the lower edge having sufficient clearance over theblades when the push plate is in the retracted position that it can beextended over the upper surface of a standard pallet without contactingthe pallet when the blades are inserted in the four-way channels of thestandard pallet.
 6. The load push mechanism of claim 5 wherein theclearance between the blades of the lift truck is sufficiently smallthat the push plate can engage a first layer of a stack of cartons offrozen animal products on a standard pallet when the blades of the lifttruck are extended into the four-way channels of the standard pallet. 7.The load push mechanism of claim 5 wherein the distance between bladesof a lift truck and the lower edge of the push mechanism is changeablebetween first and second configurations with at least one of suchconfigurations providing sufficient clearance over the blades when thepush plate is in the retracted position that it can be extended over theupper surface of a standard pallet without engaging the pallet when theblades are inserted in the four-way channels of the standard pallet. 8.The load push mechanism of claim 7 wherein the push plate includes agate mechanism operable between raised and lowered positions, the loweredge of the push plate providing sufficient clearance over the bladeswhen the push plate is in the retracted position that it can be extendedover the upper surface of a standard pallet without engaging the palletwhen the blades are inserted in the four-way channels of the standardpallet when the gate is in its raised position.
 9. The lift truck ofclaim 6 further comprising a pallet stop having an upwardly-extendingforward face, the pallet stop being mounted such that the forward faceis forward of the forward face of the push plate when the push plate isin its retracted position.
 10. The lift truck of claim 9 wherein thepallet stop comprises first and second pallet stop members, each suchmember having an upwardly-extending forward surface, and each beingmounted on the upper surface of one of the at least two blades.
 11. Thelift truck of claim 5 further comprising a pallet restraint raisable andlowerable by the lift mechanism.
 12. The lift truck of claim 11 whereinthe pallet restraint comprises a plurality of blocks, each block beingmounted, respectively, to the upper surface one of the at least two lifttruck blades, the combined thickness of the blocks and the lift truckblades being sufficiently small to allow entry of the block and bladeinto the four-way channels of a standard pallet.
 13. The lift truck ofclaim 5 wherein the pallet restraintr comprises first and secondgrippers mounted on either side of the blades of the lift truck, thegrippers being actuatable to grip a pallet by an actuator mountedbetween the first and second grippers.
 14. The lift truck of claim 5further comprising a side shift mechanism mounted between the liftmechanism and the blades for moving the blades laterally with respect tothe lift mechanism.